A member of pro-Russian forces stands guard at a checkpoint on the road from Simferopol to Sevastopol on Thursday as a Russian flag floats in the background. / Filippo Monteforte, AFP/Getty Images

by Luigi Serenelli, Special for USA TODAY

by Luigi Serenelli, Special for USA TODAY

BERLIN â?? If Crimeans vote yes in a referendum Sunday to break from Ukraine, the question is: What happens next?

Such a referendum has no precedent, analysts say, and no one appears certain how opponents, Russia and the world will react, or what difference the vote may make.

"If the referendum succeeds, you'll create a completely new situation in Crimea," said Igor Burakovsky, director of the Institute for Economic Research and Policy Consulting in Kiev.

Top diplomats for Russia and the U.S. voiced pessimism Friday about negotiating an end to the crisis. In London, U.S. Secretary of State John Kerry said he hoped to find a way to resolve the objection s the West has to a referendum it calls illegitimate.

"Obviously we have a lot to talk about," Kerry said before meeting with Russian Foreign Minister Sergey Lavrov.

The referendum asks the people of Crimea, a peninsula on the Black Sea that is part of Ukraine, if they wish to secede and join Russia or make Crimea more independent of Ukraine's federal government, run by a national parliament seated in the capital, Kiev.

Leaders of the United States and Europe have denounced repeatedly the referendum as illegal and warned it may spur civil war. Kiev says the referendum is unconstitutional and it will not recognize the results. Russia says the referendum is legitimate, and Moscow has organized rallies to welcome Crimea into the fold.

The referendum itself was drafted by members of the Crimean legislature under pressure from an armed militia that invaded the parliament and locked it down. The vote is being managed by businessmen and Crimean nationalists who have forced elected officials to resign and simply named themselves as their replacements.

President Obama on Thursday reiterated his earlier warning to Russia's President Vladimir Putin that there will be "costs" if Russia takes steps to annex Crimea after the vote. He has not said what those costs would be.

Europe and the United States could have imposed financial penalties against Russia but have not done so. Putin has retorted that any sanctions against Russia will do nothing except provoke counter-sanctions from Moscow against the USA and Europe.

Given the lack of serious action by the West, many analysts say the outcome of the crisis is squarely in the hands of Putin.

"What happens will be decided by Putin," said Kadri Liik, senior policy fellow at the European Council on Foreign Relations. "He hasn't said the final word on whether he will join Crimea with Russia or not. But all groundwork is prepared. Basically he has freedom of action."

And he has used it, with no repercussions he cannot handle, say analysts.

Thousands of Russian assault troops based at a Black Sea port that Moscow leases from Kiev have essentially invaded parts of Crimea, setting up border patrols to prevent Ukraine troops from entering the region from their bases outside Crimea.

The troop movements are a violation of a "status of forces" agreement Moscow signed with Kiev that states no Russian forces can leave the base into Ukraine. Russia has both denied and admitted that the troops, which wear no official insignia, are its own.

But Putin says Russia has the right to send troops in if it feels Russian citizens in Crimea are in danger.

The Russian assault troops appear to have coordinated efforts with armed Crimeans who have formed militias and are blocking Ukraine military bases in Crimea. Soon after the military occupation commenced, Crimeans who are pro-Moscow forced out Crimea's provincial government and appointed a little-known politician, Sergei Aksyonov, as the new regional prime minister.

"You have Russian troops on the ground â?? it cannot be considered legal â?? any referendum that happens at gunpoint is illegal," said Liik. "Plus, the referendum was announced by the new prime minister who was appointed at a session of parliament that was also at gunpoint. He got 4% of the vote at the latest local election, so he is clearly not representative, either. That is all staged by Russia."

Crimea is the only area of Ukraine where the majority of people are ethnically Russian. Crimea was made part of Ukraine in the 1950s by the defunct Soviet Union. It includes various ethnicities including Crimean Muslims known as Tatars.

But Russia has always maintained a strong presence in Crimea and Putin has lamented publicly the loss of former Soviet republics like Ukraine that declared independence after the Soviet dictatorship disintegrated and became Russia in 1991.

"Stationed in the Ukrainian city of Sevastopol, the Russian Black Sea Fleet comprises 40 vessels compared to 19 in the whole of the Ukrainian Navy," said Konrad Muzkya, a military expert at IHS Jane's in London.

Susan Stewart, deputy head of the research division on Eastern Europe and Eurasia at the German Institute for International and Security Affairs in Berlin, said Putin's aggressive stance is intended to send a message to former Soviet republics and even citizens of Russia that attempts to align with Europe rather than Russia may be met with force.

Stewart says Putin's claim that he is acting to safeguard is a smokescreen.

"If you look at the situation on the ground in Crimea in the past years, there has not been, even now, any evidence of any discrimination," she said.

Obama's steps thus far have been limited to visa bans on unnamed Ukrainian and Russian officials, preventing them from visiting the United States. Since Obama and European nations have ruled out military action, it's not clear the West will be able to get Putin to back off Crimea, say analysts.

"Russia wants the West to accept that Russia has special rights in Ukraine, which I think the West in unlikely to accept," said Liik. "But the West has no power to change the situation on the ground, either."

American and European diplomats gathered in London earlier this week to discuss further sanctions if Moscow doesn't change course. During their meeting, U.S. Secretary of State John Kerry declined to visit Moscow, saying discussions couldn't occur as long as the military intervention continues.

"Unless there is some sort of outside military intervention, there is not very much that can be changed in terms of the Russian position in Crimea," said Stewart.

As Kerry and European diplomats fretted in London, Russia and pro-Moscow Crimeans have been solidifying their hold on Crimea.

Russian troops seized more Crimean government offices and other facilities, including an airport. Pro-Russian Crimean lawmakers also passed a declaration of independence, claiming it was a necessary precursor to holding the Sunday referendum.

And Ukraine is powerless to do much other than break off economic ties with Crimea â?? which Ukraine props up economically with loans and subsidies, say analysts. Crimea could adopt the Russian ruble as its currency, but Ukraine may respond by cutting off Crimea's main supply of water, electricity and trade.

As for the use of force, Ukraine's military is outgunned by Russia and the reluctance of the West to react to the impending annexation with force would leave Ukraine no options to turn back separation of part of the country.

If that happens, Putin may set his sights more closely on other former Soviet republics, said Burakovsky.

Bordering Ukraine to the west, Moldova sits on the Black Sea and views Russia's moves in Crimea as dangerous, according to its Prime Minister Iurie Leanca.

"The tense situation in Crimea is a threat to the security of the whole region," he said this week.

Moldovans see themselves culturally as Romanian, but 200,000 people in east Moldova in the province of Transnistria, on the border with Ukraine, are ethnic Russians and have Russian citizenship.

In 1992 Russia backed an uprising there in a war that left 300 people dead. The Russian army has kept troops in the province ever since despite protests from the government.

Georgia, on the eastern shore of the Black Sea, fought a brief war in 2008 after nearly a week of clashes between Georgian troops and separatist South Ossetia, where many have Russian passports. Russia used the fighting there again as a pretext to protect its citizens and launched air attacks on Georgian forces.

Russia forces were headed to the capital of Tbilisi but pulled back to South Ossetia and Georgia's other breakaway region Abkhazia under a cease-fire agreement. It later recognized both as independent states, and Russian troops occupy them to this day.

If Crimea can hold a referendum to join Russia, other republics might call for votes to secede, too, further destabilizing the area, said Burakovsky. But Putin may not annex Crimea even if a majority of the people there wish it.

"Southern Ossetia as well as Transnistria applied but were denied," said Burakovsky, referring to attempts in those regions to join Russia officially.